PRO-4100 paper source "Cut Sheet"

[ld47]

Print Settings:
Paper Size:

• Letter(8.5"x11")(8.500x11.000)

Paper Source: 

• Cut Sheet

Layout: 

• Alignment: None 
• Move Slot: None 
• Image Slot Position/Margin:  Image Slot Position/Margin

Currently what I see in the layout is a horizontal dark gray rectangle with a horizontal white printable area rectangle, even though I'm not in landscape view.  There is an area on the right side that looks like it is not printable.

Why is the page orientation in landscape?
When I feed this sheet into the 4100, does it feed in short side first or long side first?

In other words, how do I tell in advance which side of the paper will have the extra non printable area?

[ld47]

I fed the sheet into the printer short side first. 

The far right side (dark gray non printable area) left a 3/4" (2 cm) white space that the rollers hold on to.